Wound infection is arguably the most common operative complication. It spans virtually all surgical specialties. The economic impact of wound infections is staggering, let alone the psychological cost paid by the patient. These studies address 2 issues related to this problem: first, how to predict reliably which patients are at risk for infection, and second, what is the biological basis that underlies this complication? Both studies are based on 2 decades of work by Hopf and colleagues1 that led to the hypothesis that wound infection correlates with a low oxygen wound tension. The study by Hopf et al not only confirms this hypothesis but also suggests that the measurement of oxygen tension (PsqO2) in a surrogate wound can be used to predict the patient's susceptibility to wound infection. No infection was observed when the baseline PsqO2 was 70 mm Hg or more, whereas the rate of infection